Nonlinear Seismic Responses Analysis for a Super Cooling Tower

With the rapid development of the fire power plant, an extra-large air-cooling tower (1000MW grade) will be designed and constructed in the high seismic risk areas of China such as mid-north and west-north regions. The dimension of the huge tower structure can reach up to 220 meters high and 188 meters in diameter. It's constructed with hyperboloid shell supported by X type R/C columns and the X column's length-width ratio can reach up to 1:40. It's really a challenge, but very necessary and urgent to know the seismic behavior and design weak points of the huge tower under strong earthquake attacks. This paper provides procedures and results about the modal analyses and nonlinear dynamic finite element analyses for a 220-m-high super cooling tower and its small scale (1:30) model for shaking table test under design earthquakes. The vibration modal and the seismic performance of the cooling tower, as well as the seismic damage pattern of its critical element of the support leg columns (X-pillar), were studied preliminarily. In the three-dimensional, nonlinear, dynamic time history analyses, a kind of failure criterion is adopted to simulate the possible collapse by using the LS-DYNA program. This paper provides useful reference to the seismic design practice for the extra-large tower structures.